《cuda by example》 book.h 头文件解析（转）

参考书籍 ：《cuda by example》

参考链接 ：https://code.google.com/p/snp-gpgpu/source/browse/trunk/f/common/book.h?r=4

#ifndef __BOOK_H__#define __BOOK_H__#include <stdio.h>/* cuda检错程序 */static void HandleError( cudaError_t err,const char *file,int line ) {    if (err != cudaSuccess)    {        printf( "%s in %s at line %d\n", cudaGetErrorString( err ),                file, line );        exit( EXIT_FAILURE );    }}#define HANDLE_ERROR( err ) (HandleError( err, __FILE__, __LINE__ ))#define HANDLE_NULL( a ) {if (a == NULL) { \                            printf( "Host memory failed in %s at line %d\n", \                                    __FILE__, __LINE__ ); \                            exit( EXIT_FAILURE );}}template< typename T >void swap( T& a, T& b ) {    T t = a;    a = b;    b = t;}void* big_random_block( int size ) {    unsigned char *data = (unsigned char*)malloc( size );    HANDLE_NULL( data );    for (int i=0; i<size; i++)        data[i] = rand();    return data;}int* big_random_block_int( int size ) {    int *data = (int*)malloc( size * sizeof(int) );    HANDLE_NULL( data );    for (int i=0; i<size; i++)        data[i] = rand();    return data;}// a place for common kernels - starts here__device__ unsigned char value( float n1, float n2, int hue ) {    if (hue > 360)      hue -= 360;    else if (hue < 0)   hue += 360;    if (hue < 60)        return (unsigned char)(255 * (n1 + (n2-n1)*hue/60));    if (hue < 180)        return (unsigned char)(255 * n2);    if (hue < 240)        return (unsigned char)(255 * (n1 + (n2-n1)*(240-hue)/60));    return (unsigned char)(255 * n1);}__global__ void float_to_color( unsigned char *optr,                              const float *outSrc ) {    // map from threadIdx/BlockIdx to pixel position    int x = threadIdx.x + blockIdx.x * blockDim.x;    int y = threadIdx.y + blockIdx.y * blockDim.y;    int offset = x + y * blockDim.x * gridDim.x;    float l = outSrc[offset];    float s = 1;    int h = (180 + (int)(360.0f * outSrc[offset])) % 360;    float m1, m2;    if (l <= 0.5f)        m2 = l * (1 + s);    else        m2 = l + s - l * s;    m1 = 2 * l - m2;    optr[offset*4 + 0] = value( m1, m2, h+120 );    optr[offset*4 + 1] = value( m1, m2, h );    optr[offset*4 + 2] = value( m1, m2, h -120 );    optr[offset*4 + 3] = 255;}__global__ void float_to_color( uchar4 *optr,                              const float *outSrc ) {    // map from threadIdx/BlockIdx to pixel position    int x = threadIdx.x + blockIdx.x * blockDim.x;    int y = threadIdx.y + blockIdx.y * blockDim.y;    int offset = x + y * blockDim.x * gridDim.x;    float l = outSrc[offset];    float s = 1;    int h = (180 + (int)(360.0f * outSrc[offset])) % 360;    float m1, m2;    if (l <= 0.5f)        m2 = l * (1 + s);    else        m2 = l + s - l * s;    m1 = 2 * l - m2;    optr[offset].x = value( m1, m2, h+120 );    optr[offset].y = value( m1, m2, h );    optr[offset].z = value( m1, m2, h -120 );    optr[offset].w = 255;}#if _WIN32    //Windows threads.    #include <windows.h>    typedef HANDLE CUTThread;    typedef unsigned (WINAPI *CUT_THREADROUTINE)(void *);    #define CUT_THREADPROC unsigned WINAPI    #define  CUT_THREADEND return 0#else    //POSIX threads.    #include <pthread.h>    typedef pthread_t CUTThread;    typedef void *(*CUT_THREADROUTINE)(void *);    #define CUT_THREADPROC void    #define  CUT_THREADEND#endif//Create thread.CUTThread start_thread( CUT_THREADROUTINE, void *data );//Wait for thread to finish.void end_thread( CUTThread thread );//Destroy thread.void destroy_thread( CUTThread thread );//Wait for multiple threads.void wait_for_threads( const CUTThread *threads, int num );#if _WIN32    //Create thread    CUTThread start_thread(CUT_THREADROUTINE func, void *data){        return CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)func, data, 0, NULL);    }    //Wait for thread to finish    void end_thread(CUTThread thread){        WaitForSingleObject(thread, INFINITE);        CloseHandle(thread);    }    //Destroy thread    void destroy_thread( CUTThread thread ){        TerminateThread(thread, 0);        CloseHandle(thread);    }    //Wait for multiple threads    void wait_for_threads(const CUTThread * threads, int num){        WaitForMultipleObjects(num, threads, true, INFINITE);        for(int i = 0; i < num; i++)            CloseHandle(threads[i]);    }#else    //Create thread    CUTThread start_thread(CUT_THREADROUTINE func, void * data){        pthread_t thread;        pthread_create(&thread, NULL, func, data);        return thread;    }    //Wait for thread to finish    void end_thread(CUTThread thread){        pthread_join(thread, NULL);    }    //Destroy thread    void destroy_thread( CUTThread thread ){        pthread_cancel(thread);    }    //Wait for multiple threads    void wait_for_threads(const CUTThread * threads, int num){        for(int i = 0; i < num; i++)            end_thread( threads[i] );    }#endif#endif  // __BOOK_H__